The Ptera system was situated within the Sumitra sector and included the planet known as Flax.
- Galaxy Guide 4: Alien Races (Initial mention)
- Galaxy Guide 4: Alien Races, Second Edition
- The Complete Star Wars Encyclopedia
- The Essential Atlas (referred to as Flax system)
- Star Wars: The Essential Atlas Online Companion on StarWars.com (article) (backup link) (referred to as Flax system)